A REVIEW ARTICLE ON THYROID CANCER

Thyroid cancer is the most frequent endocrine malignancy, with more than 500,000 cases per year worldwide. Differentiated thyroid cancers are the most common forms with best prognosis, while poorly/undifferentiated ones are rare (2% of all thyroid cancer), aggressive, frequently metastasize and have a worse prognosis. For aggressive, metastatic and advanced thyroid cancer novel antitumor molecules are urgently needed and phytochemical products can be a rational and extensive source, since secondary plant metabolites can guarantee the necessary biochemical variability for therapeutic purposes. Among bioactive molecules that present biological activity on thyroid cancer, resveratrol, curcumin, isoflavones, glucosinolates are the most common and used in experimental models. Most of them have been studied both in vitro and in vivo on this cancer, but rarely in clinical trials. This review summarizes phytochemicals, phytotherapeutics and plant derived compounds used in thyroid cancer.

The molecular abnormalities described here represent a broad effort during the past 20 years to understand the fundamental pathophysiology of thyroid cancer. Whereas early oncogenic events have been identified that probably account for the majority of these tumors, further study is needed to identify the incipient events in the remaining tumors. Just as critical is the need for a more comprehensive understanding of the steps that lead to progression, invasion, metastasis, and occasional dedifferentiation. An integrated framework will be required that merges knowledge of DNA mutations with understanding of the role of epigenetic alterations, changes in miRNA regulation of gene expression, and other fundamental processes that contribute to the malignant phenotype. Clinical trials of therapies to reverse genetic changes and alter complex signaling abnormalities will need to be informed by comprehensive, individualized tumor profiling that will facilitate the selection of the correct combination of therapies for each individual patient, including the identification of patients with sufficiently indolent tumors that no therapy will ever be required.